Solution processable conducting materials including metal nanoparticle inks play an important role in electronic device integrations. Silver nanoparticle inks, for example, can be easily dispersed in suitable solvents and used to fabricate various conducting features in electronic devices such as electrodes and electrical interconnectors by low-cost solution deposition and patterning techniques including ink jet printing technologies.
However, the conductive features formed from metal nanoparticle inks on suitable substrates must have sufficient adhesion and mechanical robustness characteristics to enable proper electronic device fabrications and functions. Unfortunately, adhesion of metal nanoparticle inks on certain substrates, such as glasses and polyimide, may not always be adequate for robust device fabrications.
The possibility of inadequate adhesion was tackled previously by adding a small amount of polymeric materials, such as polyvinyl butyral (PVB) resin, into silver conducting inks as an adhesion promoter. While this approach is suitable for some applications, a potential disadvantage of this method is that the electrical conductivity of printed conductive features from such inks could, in some instances, be decreased significantly. Therefore, it is desirable to develop effective methods to improve adhesion and enable formation of devices with robust mechanical properties without sacrificing electric conductivity of conducting materials, such as metal nanoparticle inks, which are used in electronic device applications.